Additive manufacturing techniques and systems to form composite materials

ABSTRACT

A printer system may include a coaxial extruder head that extrudes a core, a bulk, and/or a core and bulk cladding to form complex structures without retooling. The coaxial extruder head may include a distribution channel with an entrance and an exit, a priming chamber that surrounds the distribution channel. The priming chamber may include an outlet and a first inlet, a heating element thermally connected to the priming chamber, and a nozzle connected to the outlet of the priming chamber. Further, the nozzle may converge from the outlet of the priming chamber to an orifice of the nozzle. In addition, the exit of the distribution channel may be disposed at the orifice of the nozzle. This structure facilitates extruding a core and cladding type composite from the extruder head.

CLAIM OF PRIORITY

The present application claims priority to Provisional Application No.62/079,923, entitled “COAXIAL EXTRUSION TOOL HEAD FOR 3D PRINTERS WITHACTIVE MOLDING AND INJECTION MOLDING,” filed Nov. 14, 2014, andProvisional Application No. 62/148,174, entitled “COAXIAL EXTRUSIONTOOL, 3D EXTRUDER AND FILAMENT WINDER TECHNIQUE, AND FORMING 3DSTRUCTURES WITH HIGHLY SOLUBLE MATERIALS,” filed Apr. 15, 2015; each ofwhich is hereby incorporated by reference in its entirety.

BACKGROUND

The present disclosure relates generally to three-dimensional (3D)printers, and more specifically to the devices, assemblies andtechniques to adaptively form complex composite materials.

Most 3D printers rely on an extruder head to deposit a thin heated beadof material to specified layers to additively form an object. Theextruder head moves both horizontally and vertically to guide theplacement for each layer of the heated bead of material so that theadded material selectively produces a solid object. The properties ofthe extruded material can significantly affect the speed, precision, andquality of producing a 3D object. As such, the majority of 3D printerslimit the extruded material to a single substance. Changing the materialat various points of production to form more complex composites,although possible, is not desirable due to the significant time it takesto re-tool the extruder head and make the appropriate adjustments toachieve a high quality composite object. Accordingly, it may bedesirable to develop techniques that speed up the process, particularly,an extruder head assembly capable of producing complex compositeswithout re-tooling.

BRIEF SUMMARY

The following presents a simplified summary of one or more embodimentsin order to provide a basic understanding of such embodiments. Thissummary is not an extensive overview of all contemplated embodiments,and is intended to neither identify key or critical elements of allembodiments nor delineate the scope of any or all embodiments. Itspurpose is to present some concepts of one or more embodiments in asimplified form as a prelude to the more detailed description that ispresented later.

In some embodiments, an extruder head for a printer includes a firstdistribution channel with an entrance and an exit; a second distributionchannel with an entrance and an exit; a priming chamber disposed at theexit of the second distribution channel; a heating element disposedalong the second distribution channel and near the priming chamber; anda nozzle disposed at an exit of the priming chamber.

In some embodiments, an active molding system includes a printer havingan extruder head; and a shaping actuator configured to follow adisplacement of the extruder head, wherein the shaping actuatorincludes: a pressure regulator configured to maintain a defined pressureapplied to an exposed layer of material, and a foot unit that shapes theexposed layer of material; and a controller configured to control theprinter and the shaping actuator.

In some embodiments, a method of injection molding a composite materialincludes forming, using a printer, an object on a support structure,wherein the object includes one or more porously accessible voidedregions; enclosing the object in a mold that includes an injectionmechanism attached to the mold; and injecting a material to fill the oneor more porously accessible voided regions with the mold.

In some embodiments, a coaxial extruder head for a printer includes adistribution channel with an entrance and an exit; a priming chamberthat surrounds the distribution channel, wherein the priming chambercomprises an outlet and a first inlet; a heating element connected tothe priming chamber; and a nozzle connected to the outlet of the primingchamber, wherein the nozzle converges from the outlet of the primingchamber to an orifice of the nozzle, wherein the exit of thedistribution channel is disposed at the orifice of the nozzle.

In some embodiments, a method of winding a composite filament to form acomposite material includes rotating a mandrel about an ordinate axis,wherein the mandrel forms a 3D structure; moving a filament winding headin a direction parallel to the ordinate axis, wherein the filamentwinding head includes a coaxial extruder head; winding a filament coreand a viscous liquid around the mandrel to form the composite material.

In some embodiments, a method of winding a composite filament to form alayered composite structure includes rotating the mandrel about anordinate axis, wherein the mandrel forms a 3D structure; moving afilament winding head in a direction parallel to the ordinate axis,wherein the filament winding head includes: a printer head configured toextrude a viscous liquid through a nozzle; a filament guiding memberconnected to the printer head, wherein the filament guiding member isconfigured to guide a filament core through the viscous liquid at thenozzle; and winding the filament core and the viscous liquid around themandrel to form a layered composite structure.

In some embodiments, a fiber dispensing head for a printer includes afiber dispenser configured to dispense a fiber onto a sublayer; a nozzleconnected to the fiber dispenser and configured to eject a stream ofparticles onto the fiber; and a laser connected to the fiber dispenserand configured to heat the particles at a focal point to adhere thefiber and sublayer to form a new layer.

In some embodiments, a method of extruding material includes forming afirst support structure made of a first material and a second supportstructure made of a second material, wherein a region between the firstand second support structures is devoid of material and the bulkmaterial is insoluble; disposing a highly soluble material in the regionbetween the first and second support structures; extruding an insolublematerial over the highly soluble material; and dissolving the highlysoluble material.

In some embodiments, a method of forming a filament winding layeredstructure includes forming a 3D-print structure on a surface of acylinder using a highly soluble material to form a mandrel; rotating themandrel about an ordinate axis; moving filament winding head in adirection parallel to the ordinate axis; winding a filament around themandrel and the first and second endcap to form a layered compositestructure; placing a first endcap 525 over a first end of the layeredcomposite structure; placing a second endcap over a second end of thelayered composite structure, wherein the second endcap includes: aninlet hole between an outside surface of the second endcap and a regioninside the layered composite structure; and an outlet hole between anoutside surface of the second endcap and a region inside the layeredcomposite structure; and injecting a solvent into the inlet hole of thesecond endcap, wherein the solvent dissolves highly soluble material andexits the outlet of the second endcap.

In some embodiments, an insertion actuator for a printer includes amotor; a driver connected to the motor, wherein the motor is configuredto actuate the driver; and two or more idler bearings configured toapply a load to a portion of a filament positioned between a surface ofthe driver and a surface of the two or more idler bearings.

In some embodiments, a method of forming a material structure on asurface of an object includes depositing a first material at a firstlocation on the surface in a first direction; depositing a secondmaterial at a second location different from the first location on thesurface in the first direction, wherein depositing the second materialat the second location forms a cavity region between the first materialdeposited in the first location and the second material; and depositinga third material within the cavity region in a third direction differentfrom the first direction and the second direction to form the materialstructure on the surface of the object.

BRIEF DESCRIPTION OF THE FIGURES

For a better understanding of the various described embodiments,reference should be made to the description below, in conjunction withthe following figures in which like reference numerals refer tocorresponding parts throughout the figures.

FIG. 1A illustrates a coaxial extruder head in accordance with someembodiments of the present disclosure.

FIG. 1B illustrates a cross section of a coaxial extruder head inaccordance with some embodiments of the present disclosure.

FIG. 1C illustrates a cross section of coaxial extruder head inaccordance with some embodiments of the present disclosure.

FIG. 1D illustrates components of a controller for a printer system inaccordance with some embodiments of the present disclosure.

FIG. 2A illustrates a top view cross section of an extruded bulk beadand a side view cross section of an extruded bulk bead in accordancewith some embodiments of the present disclosure.

FIG. 2B illustrates a side view cross section layup of an extruded bulkbead in accordance with some embodiments of the present disclosure.

FIG. 3A illustrates a top view cross section of an extruded core beadand a side view cross section of extruded core bead in accordance withsome embodiments of the present disclosure.

FIG. 3B illustrates a side view cross section layup of an extruded corebead in accordance with some embodiments of the present disclosure.

FIG. 3C illustrates a top view of a planar layer with core beadspositioned according to some embodiments of the present disclosure.

FIG. 4A illustrates a top view and side view cross section of anextruded composite bead in accordance with some embodiments of thepresent disclosure.

FIG. 4B illustrates a side view cross section of a combined layup thatincludes interior and exterior regions formed layer by layer using acoaxial extruder head in accordance with some embodiments of the presentdisclosure.

FIG. 5A illustrates a side view cross section of a combined layupincluding interior and exterior regions formed layer by layer usingcoaxial extruder head in accordance with some embodiments of the presentdisclosure.

FIG. 5B illustrates a top view cross section of a combined layupincluding interior and exterior regions formed layer by layer usingcoaxial extruder head in accordance with some embodiments of the presentdisclosure.

FIG. 6 illustrates an additive manufacturing system in accordance withsome embodiments of the present disclosure.

FIG. 7 illustrates an additive manufacturing system in accordance withsome embodiments of the present disclosure.

FIG. 8A illustrates an additive manufacturing system in accordance withsome embodiments of the present disclosure.

FIG. 8B illustrates cross sections for a composite bead in accordancewith some embodiments of the present disclosure.

FIG. 9 illustrates a complex composite structure formed using a coaxialextruder head in accordance with some embodiments of the presentdisclosure.

FIG. 10 illustrates a complex composite structure formed using a coaxialextruder head in accordance with some embodiments of the presentdisclosure.

FIG. 11 illustrates a combined layup with bulk mold and an injectioncore formed using a coaxial extruder head in accordance with someembodiments of the present disclosure.

FIGS. 12A-12F illustrates an injection molding technique in accordancewith some embodiments of the present disclosure.

FIG. 13 illustrates an additive manufacturing technique in accordancewith some embodiments of the present disclosure.

FIG. 14 illustrates a molding technique in accordance with someembodiments of the present disclosure.

FIGS. 15A-15D illustrates an additive manufacturing system in accordancewith some embodiments of the present disclosure.

FIGS. 16A-16D illustrates a side view cross-section of bulk bead layersin accordance with some embodiments of the present disclosure.

FIGS. 17A and 17B illustrates a side view cross-section of compositebead layers in accordance with some embodiments of the presentdisclosure.

FIG. 18A illustrates an insertion actuator assembly in accordance withsome embodiments of the present disclosure.

FIG. 18B illustrates a side view of an insertion actuator gear inaccordance with some embodiments of the present disclosure.

FIG. 19 illustrates a side view of bulk filament threaded through aninsertion actuator assembly in accordance with some embodiments of thepresent disclosure.

FIG. 20 is a flow diagram illustrating an active molding process inaccordance with some embodiments of the present disclosure (e.g.,according to FIGS. 10 and 11).

FIG. 21 is a flow diagram illustrating a material injection process inaccordance with some embodiments of the present disclosure (e.g.,according to FIG. 14).

FIG. 22 is a flow diagram illustrating an additive manufacturing processin accordance with some embodiments of the present disclosure (e.g.,according to FIGS. 14 and 15).

FIG. 23 is a flow diagram illustrating a technique of adding layers overvoid regions accordance with some embodiments of the present disclosure(e.g., according to FIG. 16).

FIG. 24 is a flow diagram illustrating of multiple layers with someembodiments of the present disclosure (e.g., according to FIG. 17).

DETAILED DESCRIPTION

The following description is presented to enable a person of ordinaryskill in the art to make and use the various embodiments. Descriptionsof specific devices, assemblies, techniques, and applications areprovided as examples. Various modifications to the examples describedherein will be readily apparent to those of ordinary skill in the art,and the general principles defined herein may be applied to otherexamples and applications without departing from the spirit and scope ofthe various embodiments. Thus, the various embodiments are not intendedto be limited to the examples described herein and shown, but are to beaccorded the scope consistent with the claims.

Various embodiments are described below relating to adaptive fabrication(e.g., three-dimensional printing) of complex composite materials. Asused herein, “3D printing” refers to adding material layer-by-layer toproduce a solid three-dimensional object that includes formingsuccessive two-dimensional layers of predefined thicknesses. It shouldbe recognized that “3D printing” is not limited to molds or planargeometry and, in fact, may break away from the two-dimensional planethat is associated with a successive layer to form complex 3D shapes.

As used herein, “layup” may refer to the vertical topography of aresultant structure formed by depositing successive layers. Often,“layup” is depicted as a vertical cross-section.

As used herein, the term “viscous” or “viscous liquid” may refer to asubstance that is capable of flowing slowly and, in general, isrepresentative of a pliable honey-like flow. In some instances this mayrefer to a glassy material with a temperature above its glass transitiontemperature. For example, materials such as polymers (e.g. plastics,silly putty, flux, beeswax), ceramics (e.g., silicates.), sugar glass(e.g. toffee, honey), amorphous metals (e.g., metallic-glasses), abovetheir respective glass transition temperature flow malleably. In otherinstances this may refer to resins and epoxies that malleably flow underappropriate conditions (e.g. curing once exposed ultraviolet radiation,elevated temperatures).

With reference to FIG. 1A, extruder head 100 may include firstdistribution channel 110, second distribution channel 102, first nozzle103A, second nozzle 103B, priming chamber 115, heating element 105,temperature sensor 106, cutting cavity 114, blade 112, actuator 111, andheat sink 107.

In some embodiments, extruder head 100 may be configured to extrude bulk104, core 108, or a composite of core 108 that may be coaxially alignedor at least substantially coaxially aligned with bulk 104 cladding.Extruder head 100 directs core 108 through first distribution channel110 to first nozzle 103A. Second distribution channel 102 directs bulk104 to second nozzle 103B coaxially aligned with first nozzle 103A.First nozzle 103A and second nozzle 103B are aligned so that bulk 104forms a cladding that envelops core 108 filament.

Most core 108 filaments are made from sufficiently stiff materials (e.g.thermoplastics, metals) that are easily inserted and directed throughfirst distribution channel 110. For flexible core 108 filaments (e.g.,carbon fiber threads, Kevlar threads), core 108 filament may bestiffened (e.g., braided, coated) to facilitate the mechanical insertionfrom the entrance of first distribution channel 110 to first nozzle103A.

As depicted in FIGS. 1A-1C, first distribution channel 110 iscylindrical and straight, which facilitates to direct core 108 filament.Some embodiments, curve or taper (e.g., funnel-like) at least a portionof first distribution channel 110. Usually, the tapered portion isdisposed at the entrance of first distribution channel 110, whichbeneficially assist to direct core 108 filament to the exit of firstnozzle 103A. It should be appreciated that distribution channel 110 isnot limited to taper or cylindrical shapes. For example, distributionchannel 110 may have a hexagonal prism shape, rectangular prism shape.

Like core 108 filaments, many bulk 104 filaments are made fromsufficiently stiff materials (e.g. thermoplastics) that are easilyinserted and direct through second distribution channel 102. Flexiblebulk 104 filaments (e.g., epoxy resin, clay) may be stiffened (e.g.,coated) to facilitate the mechanical insertion from the entrance ofsecond distribution channel 102 to second nozzle 103B.

Like core 108 filaments, second distribution channel 102 is not limitedin shape but may have a hexagonal prism shape, rectangular prism shape.As depicted in FIG. 1A, second distribution channel 102 tapers in afunnel-like shape that contours around first distribution channel 110 toconform to and ultimately merge with priming chamber 115. In someinstances, the merge region between second distribution channel 102 andpriming chamber 115 extends over an elongated volume. For example, inFIG. 1B, each of second distribution channel 102A, third distributionchannel 102B, and fourth distribution channel 102C merge with primingchamber 115 over an elongated volume that conically tapers helicallyaround first distribution channel 110 and diminishes as the helicaltaper approaches second nozzle 103B. Likewise, FIG. 1C depicts primingchamber 115 merging with both second distribution channel 102A and thirddistribution channel 102B over an elongated volume that conically tapershelically around first distribution channel 110 and diminishes as thehelical taper approaches second nozzle 103B.

With reference to FIGS. 1A-1C, distribution channel 110 is coaxiallyaligned with second nozzle 103B, which minimizes eccentricity ofextruded core 108 with respect to bulk 104 cladding. For example, inFIG. 1A, the entrance to second distribution channel 102 is inclined atan acute angle with respect to the entrance to distribution channel 110.The acute angle assists to minimize friction between bulk 104 filamentand the walls of priming chamber 115. It should be recognized that theentrance angle is not limited to acute angles. For example, someembodiments may prefer to dispose the entrance to second distributionchannel 102 from the top (0° angle) or prefer to dispose the entrance tosecond distribution channel 102 from the side (90° angle).

In some embodiments, insertion actuator 700 (e.g., filament driver)mechanically forces bulk 104 filament into second distribution channel102 and into priming chamber 115. Heating element 105 thermally connectsto priming chamber 115 and heats bulk 104 filament above its glasstransition temperature. Inlet 118 of bulk 104 into priming chamber 115forces a coaxial bead 113 through second nozzle 103B disposed at outlet119 of priming chamber 115. As depicted in FIG. 1A, heat sink 107 isdisposed along second distribution channel 102. Heat sink 107 assists todissipate heat away from the entrance of second distribution channel 102to ensure that bulk 104 remains stiff by keeping the temperature of bulk104 filament below the glass transition temperature as bulk 104 filamententers second distribution channel 102. In some embodiments, seconddistribution channel 102 is bisected into two sections with a thermalinsulator that separates a hotter second distribution channel 102 from acooler second distribution channel 102.

In some embodiments, distribution channel 110 extends into primingchamber 115 and exits at or near the opening to second nozzle 103B frompriming chamber 115. This ensures that core 108 filament exits at thegeometric center of second nozzle 113B in a coaxial configuration.Further, this ensures that core 108 is free of bulk 104 and clear of anyobstructions when extruding the core bead 113B.

As depicted in FIGS. 1A-1C, some embodiments recess second nozzle 103Babove first nozzle 103A. Recessing second nozzle 103B may beneficiallyprevent core 108 from impinging on the edge of second nozzle 103B andmay facilitate a more symmetrical distribution of bulk 104 alongextruded bulk 104 filament at more extreme angles. Other embodimentsrecess first nozzle 103A within priming chamber 115, which may assist todraw out flexible core 108 as viscous bulk 104 passes through secondnozzle 103B. In some embodiments, first nozzle 103A and second nozzle103B are disposed in the same plane, which assists to draw out flexiblecore 108 filaments as viscous bulk 104 passes through second nozzle 103Band may provide a more symmetrical distribution of bulk 104 coaxiallyaligned with core 108 of extruded bead 113 over a range of angles.

Some embodiments include first insertion actuator 700A (e.g., filamentdriver) dispose above the entrance of first distribution channel 110that draws core 108 filament from core filament reel 109 and insertscore 108 filament into the entrance of first distribution channel 110.As depicted in FIG. 1A, some embodiments include a single inlet 118 topriming chamber 115, with second insertion actuator 700B (e.g., filamentdriver) configured to insert first bulk 104 (e.g., cladding material)into a first inlet 118A of priming chamber 115. For instance, FIG. 1Adepicts second distribution channel 102 that provides a single inlet 118to priming chamber 115.

Some embodiments include two inlets to priming chamber 115, with thirdinsertion actuator 700C (e.g., filament driver) that inserts second bulk104 (e.g., cladding material) into second inlet 118B of priming chamber115. For instance, FIG. 1C depicts second distribution channel 102A andthird distribution channel 102B with two inlets to priming chamber 115.As depicted in FIG. 1C, second distribution channel 102A and thirddistribution channel 102B are disposed symmetrically 180° apart fromeach other and tilted at an angle of approximately 75° with respect toentrance of first distribution channel 110. In some embodiments, eachinlet 118A, 118B spirals inward so as to eliminate edges, which canincrease friction between bulk 104 filament and priming chamber 115 wallas bulk 104 filament enters priming chamber 115.

Some embodiments include three inlets 118A, 118B, 118C to primingchamber 115, with a fourth insertion actuator 700D (e.g., filamentdriver) configured to insert third bulk 104 (e.g., cladding material)into third inlet 118C of priming chamber 115. As depicted in FIG. 1B,each of second distribution channel 102A, third distribution channel102B, and fourth distribution channel 102C is disposed symmetrically120° apart from the other and each is tilted at an angle ofapproximately 75° with respect to entrance of the first distributionchannel 110.

In some embodiments, the inlets spirals inward so as to eliminate edges,which can increase friction between bulk 104 filament and primingchamber 115 wall as bulk 104 enters priming chamber 115. This positionsbulk 104 filament to be in more contact with the outer wall of primingchamber 115 and closer to heating elements 105A and 105B connected tothe side of the outer wall of priming chamber 115. It should beappreciated that other embodiments may include more than three inletseach with a respective insertion actuator (e.g., filament driver)configured to insert bulk 104 (e.g., cladding material) into an inlet ofpriming chamber 115.

Further, bulk 104 filament (e.g., cladding) inserted into two or moreinlets 118A, 118B, of priming chamber 115 may be different. For example,first bulk 104 filament may include a first co-reactant material andsecond bulk 104 filament may include a second co-reactant material.Insertion of first bulk 104 filament through first inlet 118A andinsertion of second bulk 104 filament through second inlet 118B mixesboth the first co-reactant material and second co-reactant materialwithin priming chamber 115 to facilitate a reaction (e.g., cure,harden).

To assist in homogeneous mixing, each of bulk 104 filament (e.g.,cladding), the inner wall of priming chamber 115 may have helicalgrooves 119 disposed around the inner coaxial wall of priming chamber115 that corresponds to the merge region between priming chamber 115 andsecond distribution channels 102A, 102B, 102C, that extends over anelongated volume depicted in FIG. 1B and FIG. 1C. Helical grooves 119provide additional surface area, which increases heat transfer to bulk104 filament (e.g., cladding) and facilitates a homogeneous mixture. Inother embodiments, priming chamber 115 may have grooves helicallydisposed around the outer wall of priming chamber 115.

As depicted in FIG. 1B and FIG. 1C, helical grooves 119 each spiral inthe same direction. In some instances, one or more helical grooves 119may spiral in opposite directions with respect to another.

As depicted in FIG. 1A, one or more heating elements 105 are disposednear second nozzle 103B with one or more temperature sensors 106 disposeat or close to second nozzle 103B. Some embodiments include additionalheating elements 105 disposed along second distribution channel 102 toprovide a more uniform thermal gradient across second distributionchannel 102. In some embodiments, additional temperature sensors 106 aredisposed along second distribution channel 102. Temperature sensors 106may be electronic sensors (e.g., thermocouples, thermistors, diodes,transistors) or mechanical sensors (e.g., bimetal thermostat) or anythermal sensing device, that can be monitored via a computer orcontroller 160 (e.g. black body radiation detector).

Some embodiments include cutting cavity 114 that guides blade 112 to cutcore 108 filament as desired. As depicted in FIGS. 1A-1C, cutting cavity114 is disposed above priming chamber 115 and positioned to bisect firstdistribution channel 110. Some embodiments connect blade 112 to actuator111 (e.g., solenoid), which is electronically controlled to cut orperforate core 108 filament as desired. In other embodiments, blade 112is disposed at the end of first distribution channel 110 near firstnozzle 103A to cut or perforate core 108 filament, which facilitatescutting extruded core 108 at the end of bead 113.

In some embodiments, core 108 filament is impregnated with an epoxyresin as a matrix binder to increase the strength and promote adhesionto deposited bead 113. In some instances, heating elements 105 aredisabled so as not to prematurely cure the epoxy matrix binder. Otherembodiments include using ultraviolet or infrared laser 116 to providesufficient energy to cure the epoxy matrix binder. Ultraviolet orinfrared laser 116 is positioned to target the curing region of extrudedbead 113 without impeding the movement of coaxial extruder head 100.

To assist in reducing the thermal exposure of core 108 filament and heatreduction along core 108 filament, some embodiments include an insulator(e.g. thermal barrier) interposed between the exit and an entrance offirst distribution channel 110.

In some instances, first distribution channel 110 is disposed alongsidesecond distribution channel 102 with first nozzle 103A in closeproximity to second nozzle 103B (e.g., first nozzle 103A and secondnozzle 103B are side by side). This configuration facilitates extrudingseparate materials of core 108 filament or bulk 104 without re-tooling,but does not extrude a coaxial bead where bulk 104 cladding is coaxiallyaligned with core 108 filament. Instead, core 108 filament is disposedto the side of bulk 104. In this instance, bulk 104 cladding does notfully envelop core 108 filament. To ensure that bulk 104 cladding fullyenvelops core 108 filament, some embodiments rotate coaxial head 100such that bulk 104 extrudes over core 108 filament. Other embodimentsforcibly press core 108 into bulk 104 using shaping actuators 201 inactive molding process 200.

With reference to FIG. 1B, coaxial extruder head 100 includes seconddistribution channel 102A, third distribution channel 102B, and fourthdistribution channel 102C that merge with priming chamber 115 over arelatively short elongated volume. The elongation increases the internalfriction of the viscous fluid proportional to the length of the primingchamber 115. For example, coaxial extruder head 100 of FIG. 1B has lessinternal friction than coaxial extruder head 100 depicted in FIG. 1C,which includes second distribution channel 102A and third distributionchannel 102B that merge with priming chamber 115 over a relatively longelongated volume. The increase in internal friction increases the forcethreshold insertion actuator 700 exerts to push bulk 104 filament intosecond distribution channel 102.

To avoid severing bulk 104 filament from too much applied, someembodiments, include insertion actuator 700 (FIGS. 18A and 18B)configured to grip bulk 104 filament against a surface of first idler722 (FIG. 18A) bearing at a first tangential angle and a surface ofsecond idler bearing 724 (FIG. 18A) at a second tangential angledifferent from the first tangential angle.

Coaxial extruder head 100 may be configured to form homogenous bulkbeads 113A. Bulk bead 113A may be from one or more bulk 104 filamentsmixed within priming chamber 115 and extruded as bulk bead 113A.

Referring to FIG. 1D, components of controller 160 for printer 150 areillustrated in accordance with some embodiments of the presentdisclosure. For example, controller may include processor 165, memory170, and storage 175. In some embodiments, processor 165 may beconfigured to process or compute instructions and/or data. Further,memory 170 may be a physical device configured to store informationtemporarily or permanently. Additionally, storage 175 may be computinghardware that is used for storing, porting and extracting data files andobjects. Storage 175 may hold and store information both temporarily andpermanently, and can be internal or external to a computer, server orany similar computing device. In addition, bus 180 and bus connections181 and 182 may facilitate communication between various components ofprinter 150.

FIG. 2A depicts cross sections of bulk bead 113A from the top view andfrom the side view. Insertion actuator 700 mechanically forces bulk 104into second distribution channel 102 while core 108 filament is heldback. In this instance, extruder head 100 extrudes bulk 104 to providedeposited bead 113A with the material properties (e.g., stiffness andstrength) associated with bulk 104. Accordingly, the material properties(e.g., stiffness and strength) are the same in all directions (e.g.,isometric) for single layered deposited bead 113A.

FIG. 2B depicts a side view cross section of a layup structure of bulkbeads 113A. To form this structure, extruder head 100 deposits beads113A of viscous bulk 104 over previous layers. Heat exchanged fromviscous liquid bulk 104 to surrounding cooler bulk 104 bonds viscousliquid bulk 104 to adjacent cooled beads 113. The bond formed betweenadjacent beads 113A may be weaker than single bulk bead 113A andsusceptible to delamination. In some embodiments, the strength of layupof deposited bulk bead 113A is anisometric.

Coaxial extruder head 100 may be configured to form core bead 113B,which may be made from one or more core 108 filaments.

FIG. 3A depicts cross sections of core bead 113B from the top view andfrom the side view. In this instance, priming chamber 115 near theopening to nozzle 103B is de-primed to facilitate the extrusion of core108 filament without resistance from viscous liquid bulk 104. Tode-prime near the opening to nozzle 103B, insertion actuators 700mechanically retract bulk 104, which draws viscous bulk 104 away fromsecond nozzle 103B. De-priming sufficiently removes bulk 104 in regionof the end of priming chamber 115 near the opening to second nozzle103B. Once de-primed, insertion actuators 700 mechanically force core108 filament through the first distribution channel 110 and out firstnozzle 103A. In this instance, extruder head 100 extrudes core 108filament to deposit beads 113B with the material properties (e.g.,stiffness and strength) associated with core 108 filament.

In some embodiments, core 108 filaments is a metal (e.g., copper,solder, and/or alloy). In some embodiments core 108 filaments have oneor more fibers (e.g., carbon fiber, fiberglass Kevlar). In someinstances, core 108 has a much greater stiffness and strength along thelongitudinal directions of the fibers than the transverse. Accordingly,the stiffness and strength of each deposited bead 113B may beanisometric.

FIG. 3B depicts a side cross section of layup structure of core beads113B. Extruder head 100 deposits core 108 filament over previous layersand between deposited bulk 104 layers. Because core 108 filament isweaker along the transverse directions, fiber filaments 108 are oftendeposited such that the longitudinal directions of some fiber filaments108 are oriented at 90° and 45° with respect to each other, as depictedin FIG. 3C. This ensures a more overall isotropic stiffness and strengthfor fiber core layup. In some embodiments, core 108 filament may beimpregnated with an epoxy as a matrix binder to increase the strengthand promote adhesion between fibers when deposited.

Coaxial extruder head 100 may be configured to form homogenous bulkbeads 113A. Bulk bead 113A may be from one or more bulk 104 filamentsmixed within priming chamber 115 and extruded as bulk bead 113A.

Coaxial extruder head 100 may be configured to form bead 113C thatincludes core 108 filament and bulk 104 cladding. In some instances,core 108 is a metal and bulk 104 is an electrically insulated material(e.g., thermoplastic). In other instances, core 108 is a metal and bulk104 is a ceramic clay or porcelain clay. In other instances core 108 hasone or more fibers (e.g., carbon fiber, fiberglass, Kevlar) and bulk 104is a thermoplastic. In other instances core 108 has one or more fibers(e.g., carbon fiber, fiberglass, Kevlar) and bulk 104 is an epoxy.

FIG. 4A depicts cross sections of composite bead 113C from the top viewand from the side view. In this instance, first insertion actuator 700Amechanically forces core 108 filament into distribution channel 110 anda second insertion actuator 700B forces bulk 104 into seconddistribution channel 102. The resultant composite bead 113C includescore 108 and bulk 104 cladding. Composite bead 113C provides regionswith the material properties (e.g., stiffness and strength) associatedwith a both core 108 and a bulk 104.

One benefit of encasing core 108 filament with bulk 104 (e.g., cladding)is that bulk 104 protects core 108 and isolates core 108 from theenvironment. For fiber cores 108, the stiffness and strength ofcomposite bead 113C may be anisometric since many fiber core 108filaments exhibit a much greater strength along the longitudinaldirections (e.g., carbon fiber, fiberglass, Kevlar) of core 108 than thetransverse direction. In this instance, the strength in the transversedirection is greatly improved to bulk 104 cladding. The extrudedcomposite bead 113C has an anisometric distribution.

FIG. 4B depicts a side view cross section of composite layup formedusing coaxial extruder head 100. The layup includes bulk beads 113Asurrounded by composite beads 113C that have core 108 and bulk 104cladding. Extruder head 100 deposits both viscous bulk beads 113A andcomposite beads 113C of viscous bulk 104 (e.g. cladding) over previouslayers. Heat exchanged from viscous bulk 104 (e.g. cladding) to thesurrounding cooler bulk 104 bonds the viscous bulk 104 (e.g. cladding)to the adjacent cooled beads 113. The bond formed between adjacent beads113, however, is generally weaker than the single extruded bead 113 ofbulk of FIG. 4A and can delaminate. Accordingly, the strength of thelayup of the overall deposited bulk beads 113A and composite beads 113Cmay be anisometric and may be susceptible to delamination betweenadjacent beads.

Coaxial extruder head 100 may be configured to form complex materialswith regions of bulk beads 113A, regions of core beads 113B, and regionsof composite beads 113C as desired. FIG. 5A and FIG. 5B depict crosssections for a layup of a side and top view, respectively, for a complexcomposite material structure that implements a core region of core beads113B, a hybrid region of composite beads 113C, and protected by a bulkbead 113A cladding. In this instance, the interior of the structure hasan inner core of fiber core 108 and thermoplastic bulk 104 material forbulk bead 113A. In some embodiments, inner core fiber core beads 113Bmay include porously accessible voided regions 215 that are encased byboth composite bead 113C and bulk bead 113A cladding. It should beappreciated that the material comprising core 108 and bulk 104 is notlimited to fibers (e.g., carbon fiber, fiberglass, Kevlar) andthermoplastics (e.g., HDPE, PLA) but may include other materials (e.g.,metals, porcelain clay).

As described above, extruder head 100 may be configured to construct,layer by layer, each of the above structures without having to retool.It should be appreciated that numerous other structures may beconstructed by combining any of the above structures.

Active molding process 200 refers to forming and shaping techniques thatoccur while three-dimensional printing. These techniques apply pressureand temperature to the newly extruded bead in order to increase bondingbetween extruded layers and improve the surface quality. With referenceto FIG. 6, active molding process 200 includes one or more shapingactuators 201 configured to follow coaxial extruder 100 and apply bothtemperature and pressure to bulk bead 113A or core bead 113B orcomposite bead 113C. This beneficially compresses bead 113 to theprevious layer bead 113.

In some embodiments, one or more shaping actuators 201 form a sequenceof independent shaping actuators 201, where each shaping actuator 201 isconfigured to independently maintain a temperature and a pressure toextruded bead 113. Each shaping actuator 201 includes pressure regulator203 coupled to foot unit 204, temperature regulator 202, and heatingelement 105.

FIG. 6 depicts raw bead region 212, active molded region 213, andconditioned region 214. Raw bead region 212 is the shape of bead 113before active shaping actuators 201 condition the shape of bead 113.Active molding region 213 includes four independent shaping actuators201 that sequentially compresses bead 113. First shaping actuator 201Aexerts pressure, P_(A), second shaping actuator 201B exerts pressure,P_(B), third shaping actuator 201C exerts pressure, P_(C), and Nthshaping actuator 201 exerts pressure, P_(N).

Inclusive on each shaping actuator 201 is pressure regulator 203 thatsenses and applies a desired pressure. In some embodiments, pressureregulator 203 directly measure the applied pressure (e.g., via straingauges) and deliver an electrical signal to controller 160. Someembodiments include an electrical solenoid actuation as the pressureregulator that engages via controller 160. In this instance, thepressure each shaping actuator 201 exerts is proportional to the currentdriven through the solenoid. Other direct measurement embodimentsinclude a strain gage on each shaping actuator 201 to deliver anelectrical signal to controller 160 to determine the applied pressure ateach shaping actuator 201.

In some embodiments, pressure regulators 203 may indirectly determinethe applied pressure (e.g., via spring displacement). For example, asdepicted in FIG. 6, pressure regulator 203 is made of finger-likesprings that bend to engage with extruded bead 113 and exert an evenlydistributed pressure. The pressure each shaping actuator 201 exerts isproportional to the spring displacement that may be determined usingsimple calibration procedures. In these instances, the pressureincreases by moving shaping actuator 201 closer to extruded bead 113 anddecreases by moving shaping actuator 201 away from extruded bead 113(e.g., F=Kx, F is force, K is a constant, and x is displacement). Insome embodiments, pressure regulator may include a telescoping/coilspring actuator 207 that exerts force proportional to the springdisplacement as depicted in FIGS. 7 and 8. Other embodiments includehydraulic actuation that stiffens in proportion to the hydraulic fluidas pressure regulator 203. Other embodiments include a screw actuator aspressure regulator 203 that is controlled by rotating a shank usingservo motors (e.g., calibrated displacement measurement).

Shaping actuator 201 also includes shaping actuator 201 that shapesextruded bead 113. As depicted in FIG. 6, shaping actuator 201 isdisposed at the tips of the finger-like springs that make indirectcontact with extruded bead 113. In some embodiments, foot unit 204 ofeach shaping actuator 201 has different shapes. For example, shapingactuator 201 is disposed at the tips of the finger-like springs hasdifferent slopes that successively shape extruded bead 113 with eachpass. In some instances, foot unit 204 of each shaping actuator 201 isused to adjust surface roughness of extruded bead 113 or alternativelyembed objects (e.g. wires, threads, fibers) into the surface of bead 113that is subsequently covered with bead 113. For example, first shapingactuator 201 may be shaped to press core 108 filament into bulk 104 withsubsequent feet 201 shaped to form a smooth compact surface.

As mentioned above, shaping actuator 201 regulates the surfacesmoothness. Some embodiments include a coarsened roller 205 to roughenthe surface, which beneficially increases the adherence between layersby increase the surface area and contour the surface. Other embodimentsinclude a fine roller 205 to shaping actuator 201 that creates apolished surface finish. Some embodiments include knife to shapingactuator 201 that trims material for either better adherence or finersurface finish.

Pressure pulses may be added to one or more shaping actuator 201. Forexample, some embodiments include pulse actuator connected to controller160 that is configured to provide sonic or ultrasonic pulse to extrudedbeam 113. In most instances, the sonic or ultrasonic pulses increasesbond strength between extruded bead 113 and the previous layer.

In addition to exerting pressure and shaping extruded bead 113, eachshaping actuator 201 includes temperature regulator 202 that maintains adefined temperature to thermoform extruded bead 113. FIG. 6 depictsfirst shaping actuator 201 providing temperature, T_(A), second shapingactuator 201 providing temperature, T_(B), third shaping actuator 201providing temperature, T_(C), and the Nth shaping actuator 201 providingtemperature, T_(N). Temperature regulators 202 are disposed abovefinger-like springs 203. In this instance, each temperature regulator202 includes heating element 105 that transfers heat through finger-likespring 203 and shaping actuator 201 to extruded bead 113. Heated shapingactuator 201 increases pliability of extruded bead 113 and increasesbond strength between extruded bead 113 and the previous layer. Itshould be appreciated, however, that temperature regulators 202 may bedisposed in any appropriate location on foot unit 204. For example, insome embodiments, temperature regulators 202 may be disposed on shapingactuator 201.

As depicted in FIG. 6, each shaping actuator 201 subsequently compressesextruded bead 113 throughout active molding process 200 such that rawregion 212 between second nozzle 103B and first shaping actuator 201 isthe least compressed and extruded bead 113 after the Nth shapingactuator 201 is the most compressed. It should be recognized that thetemperature and pressure profile of insertion actuators 201 may vary asappropriate to the extruded material and application. For example, insome embodiments the temperature and pressure associated with eachshaping actuator 201 may be constant (e.g. T₁=T₂=T₃=T_(N) andP₁=P₂=P₃=P_(N)).

In some embodiments, each temperature regulator 202 includes temperaturesensor 106 disposed on each shaping actuator 201, preferably disposed ona position of shaping actuator 201 nearest to extruded bead 113.Temperature sensors 106 may be electronic sensors (e.g., thermocouples,thermistors, diodes, transistors) or any thermal sensing device, thatcan be monitored via a computer or controller 160 (e.g. black bodyradiation detector). A computer or controller 160 may be used to controlother components to the printer, such as, but not limited to,controlling the mechanical insertion of the bead feedstock (e.g., bulk104 and core 108) for coaxial extruder head 100, controlling actuationof extruder head 100, and/or controlling shaping actuators 201.

As depicted in FIG. 7, extruder head 100 may extrude malleablethermosetting resins 206. In some instances, shaping actuators 201provide sufficient energy to activate and regulate the curing process.For example, FIG. 7 depicts shaping actuator 201 with foot unit 204 thatconnects to a pressure regulator 203 including a telescoping/coil springactuator 207. Heating elements 105 as part of temperature regulator 202are connected above pressure regulator 203 to deliver thermal energythrough foot unit 204 to thermosetting resin 206. For example, foot unit204 forms an elongated camber shape with a curved front tip and a flatmidsection to provide more surface area in contact with thermosettingresin 206 to spread heat more evenly across the surface of thermosettingresin 206. The amount of thermal energy supplied by heating elements 105of temperature regulator 204 may be increased or decreased viacontroller 160 to accelerate or moderate the curing process accordingly.

Other embodiments for camber shaped foot unit 204 may be used. Inparticular, some embodiments may use the rocker camber shape, or theflat shape. The camber has a slight upward curve in the middle of footunit 204 that when unweighted, foot unit 204 contacts bead 113 at twocontact points between the ends of foot unit 204. The rocker cambershape has a slight downward curve in the middle of foot unit 204 thatwhen unweighted, foot unit 204 contacts bead 113 at one contact pointbetween the ends of foot unit 204. Flat shaped foot units 204 have nocurve when foot unit 204 is unweighted and contacts point between theends of foot unit 204. Further, the tips of the camber shape may have acurve up in the front near the tip, or in the back near the tip, orboth.

In some embodiments, shaping actuators 201 may include an air-blademechanism that forces a constant stream of air that impinges on thesurface of extruded bead 113. The velocity of the constant stream of airmay be increased or decreased to regulate the amount of pressure appliedto the surface of extruded bead 113. The constant stream of air may beheated at a specified temperature to transfer additional energy toextruded bead 113. In addition, the air-blade mechanism includes one ormore nozzles that shapes the exiting constant stream of air. In someembodiments, the nozzles may have a circular exit hole with a focusednon-dispersed air pattern. In some embodiments, the nozzles may have acircular exit hole that disperses the air pattern such that the airpattern forms a conical shape. In some embodiments, the nozzle may havea flat rectangular exit hole that disperses the air pattern such thatthe air pattern forms a rectangular prism-like shape.

As depicted in FIG. 8A, shaping actuator 201 delivers pressure appliedacross the surface of thermosetting resin 206 that compacts and shapesthermosetting resin 206 with each successive shaping actuator 201. Thetemperature and pressure profile of shaping actuators 201 may varyappropriately to the material properties of extruded thermosetting resin206. In some embodiments, further heating thermosetting resin 206,accelerates the curing process and consequently decreases themalleability of extruded bead 113. Thus, the curing rate of extrudedbead 113 may be proportional to the thermal gradient of extruded bead113, so that the fastest curing rate occurs in the hotter areas near thecontact region of the elongated foot unit 204 and the slowest curingrate occurs near the cooler areas near contact regions of previouslayers.

To reduce any disproportionate curing rate, printer system of thepresent application may include a laser 116 to apply optical energy toareas of thermosetting resin 206 that contacts previous layers. Asdepicted in FIG. 7, ultraviolet laser 116 may be positioned to target alocation near foot unit 204 of shaping actuator 201 to irradiate thesurface of thermosetting resin 206 that contacts previous layers. Insome embodiments, ultraviolet laser 116 may be a continuous beam wherethe intensity and total output power can be regulated appropriate to thematerial properties of extruded thermosetting resin 206. In someembodiments, ultraviolet laser 116 may include a pulsed beam with aspecific intensity. In other embodiments, it may be beneficial to have acombination of continuous and pulse beam intensity from ultravioletlaser 116. It should be appreciated that laser 116 is not limited tooutput ultraviolet spectrum and may output power at any appropriatewavelength, such as infrared, visible, and/or deep ultraviolet. Further,a computer or controller 160 may be used to control the position and theoutput power of laser 116.

In some embodiments, the laser 116 is positioned to target bead 113 nearfirst nozzle 103A or second nozzle 103B of extruder head 100. Often,targeting a location near first or second nozzle 103A, 103B providessufficient stiffness in thermosetting resin 206 to facilitate beadplacement. In other embodiments, multiple lasers 205 may be included totarget regions of thermosetting resin 206 to facilitate bead placementand shaping, as well as, increase curing rates, and facilitate layercompaction. In some embodiments, for a wider target distribution heatlamps may be used.

FIG. 8A depicts, a 3D printer system that includes extruder head 100configured to extrude malleable thermosetting resin 206 surrounding acore 108. As depicted, ultraviolet laser 116 targets a location nearfirst nozzle 103A of extruder head 100 and is positioned to irradiatethe surface of thermosetting resin 206 that contacts the previousdeposited layer. The added energy provided by laser 116 compliments theapplied energy using shaping actuators 201 to actively mold extrudedthermosetting resin 206 to previous layers.

FIG. 8B depicts the cross section of raw extruded bead 113 (e.g., atlocation R), the cross section shape after first shaping actuator 201A(e.g., at location A), the cross section shape after second shapingactuator 201B (e.g., at location B), and the cross section shape afterNth shaping actuator 201N (e.g., at location N).

As depicted in FIG. 8B, active molding process 200 shapes and contoursthermosetting resin 206 to the surface of the previous layer. Forexample, the side view cross section of extruded raw bead 113 includes asquare core 108 concentric to a circular thermosetting resin 206cladding. In contrast, once bead 113 is compacted and shaped by firstshaping actuator 201A thermosetting resin 206 of extruded bead 113elongates in the longitudinal and transverse directions. Second shapingactuator 201B further compacts and elongates bead 113 in thelongitudinal and transverse directions to form a more rectangular shapecross section with rounded corners. Last shaping actuator 201N forms themost compacted shape of bead 113 of FIG. 8A such that the cross sectionforms a rectangular shape that sufficiently contours to the previoussurface and fills in void regions 215 such as the rounded corners.

One benefit in using extruder head 100 and shaping actuators 201 is thata printer system actively shapes complex hybrid structures withouthaving to retool. In reference to FIG. 9, extruder head 100 extrudescore 108 and a cladding material to form hybrid composite structure 211.As depicted in FIG. 9, core 108 is pre-impregnated with epoxy resin thatactivates with ultraviolet light and bulk 104 axially forms a claddingaround impregnated core 108.

In some embodiments, foot unit 204 of shaping actuators 201 isconfigured to engage and shape regions of extruded bead 113 that withpre-impregnated core 108. First shaping actuator 201 includes foot unit204 that connects to pressure regulator 203 including an electricalsolenoid actuator for fast actuation of first shaping actuator 201. Thispermits first shaping actuator 201 to engage and disengage fromimpregnated core 108 regions without impinging on adjacent claddingmaterial along the longitudinal length of extruded bead 113.

As depicted in FIG. 9, active molding process 200 may use ultravioletlaser 116 to target extruded bead 113 in a region near shaping actuator201. Ultraviolet laser 116 accelerates the curing of the epoxy tostiffen the epoxy while shaping actuator 201 presses core 108 against aprevious layer of cured epoxy core 108.

Each remaining shaping actuator 201 of shaping actuators 201 isconfigured to engage with bulk 104 cladding. Each shaping actuator 201has a telescoping/coil spring actuator 207 and a foot unit 204 thatconnects to a pressure regulator 203. Heating elements 105 fromtemperature regulator 202 are connected above pressure regulator 203 todeliver thermal energy through foot unit 204 to bulk 104 cladding. Asdepicted in FIG. 9, each remaining shaping actuator 201 presses againstbulk 104 cladding and actively compacts and shapes the cladding tocontour around previous layers.

Hybrid composite structure 211 includes voided regions 215 that areporously accessible to adjacent voided regions 215. In some embodiments,the inclusion of voided regions 215 reduces the weight of the overallhybrid material composite beneficially resulting in strong light-weightcomposites applicable in many mechanical and aeronautical designs. Theinclusion of voided regions 215 is also applicable for designs thatfavor strong materials with high thermal insulative properties. In manyinstances, voided regions 215 of FIG. 9 may be filled with gases such asair, nitrogen, and/or argon, which may be realized by enclosing theentire 3D printing system in a sealed chamber filled with the desiredgas.

In some embodiments, injection mechanism 304 may be included to inject asubstance into porously accessible voided regions 215. For example, asillustrated in FIG. 11, hybrid composite structure 211 is disposed on anunderlying support structure 210 that forms an A-side mold 306 similarto FIG. 10. FIG. 10 also depicts mold cavity 313 that forms a B-sidemold 306 that seals with the A-side mold 306 to enclose the entirehybrid composite structure 211. Injection mechanism 304 is included onthe A-side mold 306 with inlet 314 and outlet 317. Inlet 314 injects asubstance into voided porous regions 215 of hybrid composite structure211 while outlet 317 purges the air from voided regions 215. It shouldbe appreciated that forming voided regions 215 that are porouslyaccessible to injection mechanism 304 facilitates the injection moldingprocess and reduces the likelihood of void pockets in the final product.Further, injecting bulk fluid 302 under pressure may assist ineliminating voided regions 215 especially for capillary sized voidedregions 215.

In some embodiments, hybrid composite structure 211 is heated in an ovento a high-temperature in an oxygen-free environment until bulk 104undergoes pyrolysis. Subsequent hybrid composite structure 211, onceencased within mold cavity 313 and support structure 210, may beinjected with a liquid metal to yield a complex alloy structure.

In some embodiments, the injected substance is an epoxy based secondarymatrix that may include matrix strengthening fibers such as glass,carbon fiber, steel particles, nano-sized ceramic powders, and the like.In some embodiments, the injected substance is a sinterable wax that mayinclude fine sinterable particles such as glass, ceramic powders,metallic powders, and/or semiconductor powders.

Coaxial extruder head 100 may also be configured to form structures withan internal framework (e.g. scaffold) that include void region 215 thatare porously accessible. In some embodiments, void regions 215 withstructures that are subsequently filled with bulk fluid 302 usinginjection mechanism 304 (e.g. injection molding, submersion, vacuumdisplacement).

One technique to inject bulk fluid 302 is to include outlet 317 andchannel structure 314 as part of injection mechanism 304 in mold 300. Asdepicted in FIG. 11, bulk fluid 302 is inject via injection mechanism304 to fill voided regions 215. In this instance, the structure depictedin FIG. 11 includes an inner core of core beads 113B enclosed incomposite beads 113C that is encased by an exterior bulk beads 113Acladding. The topology further includes injection mechanism 304, whichprovides access between the outside of the exterior bulk 104 shell andthe inner core region. During the injection process, bulk fluid 302flows through channel structure 314 and pushes the ambient fluid (e.g.,air, inert gas) out through outlet 317. Some embodiments include one ormore outlets 317 to facilitate the outflow of ambient fluid (e.g., air,inert gas) from the structure.

Another technique to inject bulk fluid 302 is to include channelstructure 314 to a hermetically seal structure without outlets 317 inmold 300. In this instance, channel structure 314 provides accessbetween void regions 215 and the outside the structure. Connecting avacuum pump and via injection mechanism 304 removes the ambient fluid(e.g., air, inert gas) from void regions 215 within the structure.Stopping value 305 holds the vacuum within the structures. Connecting aninfusion device 301 (e.g., syringe) filled with bulk fluid 302 toinjection mechanism 304. Finally, unstopping value 305 ingresses bulkfluid 302 and fills void regions 215 with bulk fluid 302. Sufficientbulk fluid 302 should be provided in the infusion device 301 (e.g.,syringe) to adequately fill voided regions 215 within the hermeticallysealed bulk 104 cladding.

Another technique to inject bulk fluid 302 is to submerse a structure ina container of bulk fluid 302. In this instance, the bulk fluid 302 orambient fluid (e.g., air, inert gas) flows through either injectionmechanism 304 or outlets 317 to fill void regions 215 with bulk fluid302. Once filled, value 305 may be closed and one or more outlet 317 maybe stopped prior to removing mold 300 from the container of bulk fluid302.

In some embodiments, bulk fluid 302 is an epoxy or an epoxy thatincludes fibers. In some embodiments, bulk fluid 302 is a liquid metal.In some embodiments, the structure includes core beads that are porousfibers. It should be appreciated that the mechanism to inject the bulkfluid 302 is not limited to infusion device 301 (e.g., syringe) andother mechanism as are also possible, such as, but not limited towicking, capillary action, and/or infiltration.

In some embodiments, the composite structure may form a temporary moldthat is removed after the injection molding process. For example, inreference to the technique depicted in FIGS. 12A-12E, extruder head 100may be configured to form A-side mold 306 and/or B-side mold 306 thatmay be used for injection molding to fill voided regions 215. Asdepicted in FIG. 12A, A-side mold 306 may be the support structure andmay be made from thermoplastics, clays, and/or epoxy resins. B-side maybe made from any removable material that may be formed into complexstructures using extruder head 100. Removable materials may includedissolvable thermoplastic such as ABS or high impact polystyrene (HIPS)that dissolves in liquid solution 310 (e.g., solvent) or compostablematerial that may be removed through microbial activation (e.g.,biodegradable) such as polylactic acid (PLA), and/or polyglycolic acid(PGA).

As depicted in FIG. 12C, A-side mold 309 and the B-side mold 306 form amateable assembly that includes injection mechanism 304 with inlet 314and outlet 317. Inlet 314 inflows bulk fluid 302 into porous voidedregions 215 of B-side mold 306 made from HIPS while outlet purges 317the air from voided regions 215. FIG. 12D depicts injecting bulk fluid302 using injection mechanism 304. In this instance, bulk fluid 302 usedin the injection mechanism is a thermal epoxy resin that cures afterinjection.

Once the epoxy is sufficiently cured, the assembly is placed into liquidsolution 310 such as a limonene solution to remove the B-side mold 306,as depicted in FIG. 12E. The resultant object, as depicted in FIG. 12Fforms a model tree where A-side mold 306 is integrated into the objectto form the trunk of the model tree and the injected epoxy resin formsthe foliage 307B. Note that intricate surface regions within the foliageare present and realized through the inclusion of material from B-sidemold 306 that is removed by dissolution.

It should be appreciated that the material used to form the A-side 309and B-side 306 mold are not limited to epoxies or thermoplastics. Forexample, in some embodiments, bulk 104 may be a ceramic clay orporcelain clay. The clay may be sintered in a subsequent step to form astrong heat-resistant A-side 309 or B-side 306 sintered mold 300. Theinjected fluid 302 may be a ceramic or metallic powder impregnated witha wax that when heated viscously flows into the porously accessiblevoided regions 215 of a sintered clay mold 300. A subsequent heatingprocess can remove the wax from sintered clay mold 300. An additionalsintering process sinters the ceramic or metallic powders within thesintered clay mold 300. The sintered clay mold 300 may be removed toreveal the object or left intact with the ceramic or metallic powder.Further, the metallic or ceramic powders may be mixed to form alloys orcermets once sintered.

In addition to a ceramic precursor clay or porcelain clay as a claddingmaterial, some embodiments may use core made from metallic wire orsemiconductor filament instead of a core 108 filament.

The material used in 3D printing may undergo subsequent processing stepsto achieve the preferred material properties. For example, in someembodiments a thermoplastic may undergo pyrolysis in a high temperatureand oxygen-free environment. In this instance, the high carbon residuefrom the pyrolysis is the desired structure that is obtained through thecontrolled breakdown of the thermoplastic that was formed through activemolding process 200. It should be recognized that without the controlledoxygen-free environment, the thermoplastic may be significantly damagedonce the temperature is elevated. Likewise, it should be recognized thateach subsequent process, in general, should be subject to less energeticprocess step to ensure that the structure and materials are not damagedin the process flow. This reduction in energy for subsequent steps isreferred as energy cascade.

Further, leveraging the energy cascade of subsequent processingtechniques with active molding process 200 described above facilitiesthe manufacturing of complex structures. For example, a monolithic brakerotor and wheel may be formed using coaxial extruder head 100 andshaping actuators 201 with subsequent controlled processing that followsthe energy cascade. In some embodiments, the brake rotor may includethree parts: a thermoplastic wheel reinforced with ultra-high molecularweight polyethylene fibers, a carbon fiber reinforced silicon carbide,SiC, brake rotor, and a titanium heat sink that attaches the wheel tothe brake rotor. In this instance, the energy cascade indicates thattitanium heat sink should be formed first, followed by the brake rotor,and the reinforced wheel.

To from the titanium heat sink, a titanium powder with a thermoplasticwax binder is extruded using extruder head 100 to form a structure thatis about 20% wax. The structure is then heated in a controlled lowoxygen, near vacuum environment at around 500° C. This step removes thewax and the thermoplastic undergoes pyrolysis. The titanium heat sink isthen placed into a sintering oven at around 1400° C. to sinter thetitanium into solid nonporous monolith titanium structure.

Next, the titanium heat sink is disposed on a support structure andextruder head 100 3D prints a brake rotor structure including a carbonfiber core 108 with thermoplastic cladding. In some instance, thethermoplastic may have pure carbon as an additive. The resultantstructure is then heated in a controlled oxygen-free environment ataround 500° C. to undergo pyrolysis and reduce the thermoplasticcladding to pure carbon. At this point, the brake rotor has titaniumheat sink with a porous carbon/carbon composite rotor.

A dissolvable thermoplastic molding shell is 3D printed using extruderhead 100 and shaping actuators 201 to form a mold around the porouscarbon/carbon brake rotor. Then a high carbon content epoxy is injectedinto the porous brake rotor. After the epoxy cures at around 200° C.,the thermoplastic is dissolved at around 100° C. using a limonenesolvent. The resultant structure is then heated in a controlledoxygen-free environment at around 500° C. to undergo undergoes pyrolysisand reduce the thermoplastic cladding to pure carbon. At this point, theporosity of the carbon/carbon portion of the rotor is greatly reduced.

A stoichiometric balance is reached by submerging the porouscarbon/carbon brake rotor in liquid silicon at around 1400° C. toinfiltrate voided region 215 (e.g., porous capillary regions). Morespecifically, the liquid silicon flows through the porous capillariesand fills the voided region 215 to about 99% solidity. In someinstances, a portion of the porous carbon/carbon brake may be submersedin the liquid silicon to wick the non-submersed portion and infiltratesvoided region 215 (e.g., the porous capillaries) of the carbon/carbonbrake. When the silicon cools, it bonds with the titanium and carbonmatrix and forms a silicon carbide/carbon brake rotor.

The final process is to use extruder head 100 to 3D print an ultra-highmolecular weight polyethylene reinforced PEI wheel onto the heat sinkportion of the brake rotor.

As described above, the materials used may include metals,semiconductors, plastics, ceramics and the like, where each material issusceptible to a temperature as a processing step, (e.g., sintering,glass transition).

With reference to FIG. 13, fiber dispensing head 400 uses core 108(e.g., fiber) dispenser to dispense core 108 (e.g., fiber) onto asublayer. Particle nozzle injector 401, connected to core 108 (e.g.,fiber) dispenser, is configured to eject stream of particles 403 ontocore 108 (e.g., fiber). Laser 116, connected to core 108 (e.g., fiber)dispenser, is configured to heat particles 403 at a focal point 404 suchthat particles 403 adhere core 108 (e.g., fiber) and sublayer to form anew layer. In some embodiments, fiber dispensing head 400 includes motor707 connected to a gripper-roller (e.g., idler bearings 722 and/or 724)and configured to rotate the gripper roller (e.g., idler bearing), todirect core 108 (e.g., fiber) from through first distribution channel110 to the sublayer. In some embodiments, particles 304 ejected byparticle nozzle injector 401 includes metal.

As depicted in FIG. 13, some embodiments may have more than one particlenozzle injector 401. Some embodiments that have more than one particlenozzle may eject different particles 403. In some embodiments, the heatgenerated by laser 116 melts particles 403 ejected by particle nozzleinjector 401. For example, particles 403 ejected from one particlenozzle injector 401 may include solder and second particle nozzleinjector 401 may include flux. The heat generated by laser 116 may flowthe solder over core 108 (e.g., fiber).

This technique may also be used to produce alloys. For example, toproduce a layer of brass, the ejected particles 403 from one particlenozzle injector 401 may include copper and second particle nozzleinjector 401 may include zinc. Once laser heated, the copper and zincmelt to form brass over core 108 (e.g., fiber).

In some embodiments, laser 116 outputs infrared spectrum. Further, insome embodiments, laser 116 may not have sufficient power to meltparticles 403. In these instances, the heat generated by laser 116sinters particles 403 ejected by particle nozzle injector 401. This maybe beneficial in instances of creating porous objects that may be filledthrough capillary action. For example, sintering the ejecting nano-sizedmetallic particles 403 provides porously accessible void regions 215within an object. Subsequently, submerging the object in a liquid metal,the porously accessible void regions 215 fill with the liquid metal toform a composite over core 108 (e.g., fiber).

With reference to FIG. 14, coaxial extruder 100 may be used to wind afilament (e.g., core 108 and bulk 104) to form a composite materiallayered about a 3D structure. As depicted, a printer system including anextruder (e.g. coaxial extruder 100, FIG. 1A-1C) may rotate mandrel 501about an ordinate axis. In some embodiments, mandrel 501 forms a 3Dstructure. A printer system including an extruder (e.g. coaxial extruder100, FIG. 1A-1C) may move a filament winding head in a directionparallel to the ordinate axis. In some embodiments, the filament windinghead includes coaxial extruder head 100. Further, a printer systemincluding an extruder (e.g. coaxial extruder 100, FIG. 1A-1C) may wind afilament core 108 and a bulk 104 (e.g., viscous liquid) around themandrel to form the composite material.

In some embodiments, coaxial extruder 100 depicted in FIGS. 1A-1C may beused to filament wind. For example, coaxial extruder 100 depicted inFIG. 1A may be used with a thermoplastic cladding (e.g., bulk 104) andcarbon-fiber core (e.g., core 108). Likewise, the coaxial extruderdepicted in FIGS. 1A-1C may use an epoxy cladding (e.g., bulk 104) and aKevlar fiber core (e.g., core 108). In some embodiments, a tensioner maybe used to maintain a tensional force to the extruded compositematerial.

With reference to FIGS. 15A-15D, an additive manufacturing system isillustrated in accordance with some embodiments of the presentdisclosure. A printer system including an extruder (e.g. coaxialextruder 100, FIG. 1A-1C) may form a filament winding layered structure502 on mandrel 501 may combine 3D printing on mandrel 501 to custom the3D structure. As depicted, the process first involves, forming a3D-print structure 526 on a surface 510 of a cylinder using a highlysoluble material 605 to form mandrel 501. The printer system includingan extruder (e.g. coaxial extruder 100, FIG. 1A-1C) may rotate mandrel501 about an ordinate axis. Further, the printer system including anextruder (e.g. coaxial extruder 100, FIG. 1A-1C) may move filamentwinding head in a direction parallel to the axis. In addition, theprinter system including an extruder (e.g. coaxial extruder 100, FIG.1A-1C) may wind a filament (e.g., core 108 and bulk 104) around theelastic bladder mandrel to form layered composite structure 502.

To release layered structure 502 from mandrel 501, the printer systemincluding an extruder (e.g. coaxial extruder 100, FIG. 1A-1C) may placea first endcap 525 over a first end of layered composite structure 502and place a second endcap 522 over a second end of layered compositestructure. In some embodiments, second endcap 522 may include inlet hole523 between an outside surface of second endcap 522 and a region insidelayered composite structure 502, and an outlet hole 524 between anoutside surface of second endcap 522 and a region inside layeredcomposite structure 502. Further, the printer system including anextruder (e.g. coaxial extruder 100, FIG. 1A-1C) may inject liquidsolution 310 (e.g., solvent) into inlet hole 523 of second endcap 522,wherein liquid solution 310 (e.g., solvent) dissolves highly solublematerial 605 and exits outlet 524 of second endcap 522.

Because the material custom printed on cylinder (e.g. mandrel 501) ofthe material is highly soluble (e.g., highly soluble material 605), thistechnique beneficially provides fast separation and removal of mandrel501 without damaging the formed layered structure 502. In someembodiments an elastic bladder may be placed over mandrel 501 prior towinding. This facilitates a hermetical seal between first endcap 525 tothe elastic bladder and second endcap 522 to the elastic bladder.Further, this beneficially encloses liquid solution 310 (e.g., solvent)that is injected through inlet hole 523 and through outlet hole 524 ofsecond endcap 522.

With reference to FIG. 16A-16D, the extruder head includes a firstextruder configured to deposit insoluble material, e.g. thermoplastics,and a second extruder configured to deposit a highly soluble material.This extruder facilitates the technique of using highly soluble materialto bridge regions devoid of structure in the final object.

Referring to FIGS. 16A-16D, a side view cross-section of bulk beadlayers is illustrated in accordance with some embodiments of the presentdisclosure. A printer system including a coaxial extruder (e.g., coaxialextruder 100, FIGS. 1A-1C) may form first support structure 130A made ofa first material (e.g., bulk 104A) and a second support structure 130Bmade of a second material (e.g., bulk 104B). In some embodiments, aregion between the first and second support structures is devoid ofmaterial (e.g., void region 215) and the bulk material is insoluble. Theprinter system including a coaxial extruder (e.g., coaxial extruder 100,FIGS. 1A-1C) may dispose highly soluble material 605 in the regionbetween first and second support structures 130A, 130B. Further, theprinter system including a coaxial extruder (e.g., coaxial extruder 100,FIGS. 1A-1C) may extrude an insoluble material over the highly solublematerial 605; and dissolving the highly soluble material.

In some embodiments, first and second support structures 130A, 130B spanmultiple layers. Prior to disposing highly soluble material 605 in voidregion 215 between first and second support structures 130A, 130B. Firstand second support structures 130A, 130B provide support to depositbridge 606 layer that is disposed over both bulk 104 and highly solublematerial 605 as a ‘bridge.’ As depicted in FIG. 16A-16D the six layersthat make up first and second support structures 130A, 130B are disposedprior to disposing highly soluble material 605.

In some embodiments, highly soluble material 605 may be dispensed at adefined rate. As depicted in FIG. 16B, some or the majority of highlysoluble material 605 fills void region 215 at high rate 602.Subsequently, coaxial extruder slows to modest rate 603 to fill voidregion 215 moderately but, for the most part, with more precision thanhighest rate 602. Coaxial extruder further slows to low rate 603 toensure a smooth uniform surface for the top of the highly solublematerial 605 layer. The uniformity of the top of the highly solublematerial 605 layer correlates to a smooth uniform bottom surface 607(FIG. 16D) to bridge 606.

As depicted in FIG. 16C, coaxial extruder 100 deposits bridge 606 overfirst support structures 130A, highly soluble material 605, and secondsupport structures 130B. As depicted, outlets 317 are included in bridge606 to facilitate access of liquid solution 310 (e.g., solvent) betweenthe outer surface of bridge 606 and highly soluble material 605. Itshould be appreciated that bridge 600 projects along the x-y plane andincludes multiple adjacent layers and some bridge 606 layers may notinclude outlets 317.

As depicted in FIG. 16D, the formed object is submerged in liquidsolution 310 (e.g., solvent) to dissolve highly soluble material 605.Some embodiments may include injection mechanism 304 with inlet 314 andoutlet 317 to facilitate the dissolution of highly soluble material 605.

In some embodiments, coaxial extruder head 100 may dispose highlysoluble material 605 in void region 212 between first and second supportstructures 130A, 130B successively. This beneficially provides asublayer without voids.

In some embodiments, highly soluble material 605 is a sucrose based“frosting” that quickly dissolves in water. In some embodiments, bulk104 is a thermoplastic.

With reference to FIGS. 17A and 17B, a side view cross-section of acomposite bead layer deposition process is illustrated. For example, acomposite bead layer may include core 108 core and bulk 104 cladding toform three-dimensional printed layup with voided regions 215. Coaxialextruder 100 subsequently fills voided region 215 with an extrudedcomposite bead 113C with core 108 and bulk 104 cladding.

In some embodiments, the bead layer deposition process may be performedat or by a printer system including extruder head (e.g., extruder head100, FIGS. 1A-1C). Specifically, for example, printer system includingextruder head (e.g., extruder head 100, FIGS. 1A-1C) may initiallydeposit first material (e.g., bulk 104 and core 108) at first location145 on the surface in a first direction (e.g., z-direction).

Printer system including extruder head (e.g., extruder head 100, FIGS.1A-1C) may deposit a second material (e.g., bulk 134 and core 138) atsecond location 146 different from first location 145 on the surface inthe first direction (e.g., z-direction). In some embodiments, depositingsecond material (e.g., bulk 134 and core 138) at second location 146forms cavity region 601 between first material (e.g., bulk 104 and core108) deposited in first location 145 and second material (e.g., bulk 134and core 138). Further, printer system including extruder head (e.g.,extruder head 100, FIGS. 1A-1C) may deposit a third material (e.g., bulk144 and core 148) within cavity region 601 in a second directiondifferent from the first direction (e.g., z-direction) to form thematerial structure on the surface of the object.

In some embodiments, printer system including extruder head (e.g.,extruder head 100, FIGS. 1A-1C) may repeat the depositing of the firstmaterial (e.g., bulk 104 and core 108) at first location 145 and secondmaterial (e.g., bulk 134 and core 138) at second location 146 until athreshold material limit is met. In some instances, the thresholdmaterial limit may be a height of one or both of first material (e.g.,bulk 104 and core 108) at the first location 145 or the second material(e.g., bulk 134 and core 138) at the second location 146.

In some embodiments, the first direction is parallel to the surface ofthe object and the second direction is perpendicular to the surface ofthe object. In some embodiments, the first direction is perpendicular tothe surface of the object and the second direction is parallel to thesurface of the object. In some embodiments, depositing the firstmaterial, the second material and the third material includes depositingusing an extruder head (e.g., extruder head 100, FIGS. 1A-1C). In someembodiments, the first material (e.g., bulk 104 and core 108) and thesecond material (e.g., bulk 134 and core 138) are different materials.In some embodiments, the first material and the second material aresimilar materials.

In some embodiments, printer system including extruder head (e.g.,extruder head 100, FIGS. 1A-1C) may fill cavity region 601 with thirdmaterial (e.g., bulk 144 and core 148). For example, cavity region 601may accommodate a volume larger than bead width of third material (e.g.,bulk 144 and core 148) from extruder head (e.g., extruder head 100,FIGS. 1A-1C). In these instances, extruder head (e.g., extruder head100, FIGS. 1A-1C) may fill cavity region 601 in a manner that overlapsof tangles core 148 within cavity region 601.

FIG. 18A illustrates an insertion actuator assembly for a printer inaccordance with some embodiments of the present disclosure. For example,insertion actuator assembly 700 includes insertion actuator driver/gear701 (e.g., filament drive gear) with four low-friction idler bearingspositioned to contour bulk 104 filament or core 108 filament aroundinsertion actuator gear 701 (e.g., filament drive gear).

Although shown using four low-friction idler bearings, it should beunderstood that insertion actuator assembly may include two or moreidler bearings configured to apply a load to a portion of a filamentpositioned between a surface of the driver and a surface of the two ormore idler bearings. In some embodiments, idler bearings may includefirst idler bearing 722 and second idler bearing 724. For instance,insertion actuator driver/gear 701 may direct the portion of thefilament against a surface of first idler bearing 722 at a firsttangential angle and a surface of second idler bearing 724 at a secondtangential angle different from the first tangential angle. Further, thesurface of the two or more idler bearings 722 and 724 may includecontours to the filament and/or ridges.

Insertion actuator assembly 700 may also include motor 707 to drive oractuate insertion actuator driver/gear 701, which in turn, directs thefilament in a direction corresponding to a rotation of actuatordriver/gear 701. As such, insertion actuator driver/gear 701 may beconnected to the motor 707. Further, insertion actuator assembly 700 mayinclude load distribution assembly 720, which may be configured toadjust and maintain a load or force to the filament. Load distributionassembly 720 may include member 703 configured to connect to the firstidler bearing 722 and the second idler bearing 724. In some embodiments,the member 703 may be configured to distribute a load between the firstidler bearing 722 and the second idler bearing 724. Further, loaddistribution assembly 720 may include at least one spring 709 coupled tofirst adjustment member 706 (e.g., knob).

In addition, load distribution assembly 720 may include lever 704connected to the member 703, and which may be configured to redistributethe load between the first idler bearing 722 and the second idlerbearing 724. In some embodiments, load distribution assembly 720 mayinclude second adjustment member 705 (e.g., knob) coupled to the lever704. For example, load distribution assembly 720 may be configured toadjust a distribution of the load or force (e.g., F₁, F₂, F₃, and/or F₄)via lever 704 based on adjusting second adjustment member 705 (e.g.,rotating the knob in a clockwise or counterclockwise direction).Accordingly, one or more of the load or force applied by first idlerbearing 722 (F₁, F₂) and/or the load or force applied by second idlerbearing 724 (F₃, F₄) may be adjusted using lever 704. As such, acontour, size, shape, and/or thickness of a filament may becorrespondingly adjusted as it enters and travels between insertionactuator driver/gear 701 and idler bearings 722 and 724, as shown inFIG. 19.

FIG. 18B illustrates a side view of insertion actuator driver/gear 701in accordance with some embodiments of the present disclosure. Forexample, insertion actuator driver/gear 701 (e.g., filament drive gear)may include one or more ridges or contours 708 disposed around groovecircumference 711. In some embodiments, the surface of insertionactuator driver/gear 701 may include one or more concave ridges, one ormore angled ridges, and/or one or more convex ridges.

FIG. 20 is a flow diagram illustrating active molding method 800 inaccordance with some embodiments of the present disclosure.Specifically, method 800 provides for forming complex compositestructures in accordance with some embodiments. In some embodiments,method 800 may be performed at or by printer 150 including coaxialextruder 100 (FIGS. 1D and 6-9). Some blocks and/or operations in method800 may be combined, the order of some blocks and/or operations may bechanged, and some blocks and/or operations may be omitted.

At block 820, method 800 may form, using a printer, an object on asupport structure. For example, as described herein, printer 150 (FIG.1D) may drive the coaxial extruder 100 (FIGS. 1A-1C) to form compositestructure 211 (FIG. 9) on support structure 210 (FIG. 9). In someembodiments, the object includes one or more porously accessible voidedregions.

At block 830, method 800 may enclose the object in a mold that includesan injection mechanism attached to the mold. For instance, as describedherein, mold cavity 313 (FIG. 10) may enclose (e.g., partially orcompletely) composite structure 211 (FIGS. 9-10) in a mold 300 (FIGS.10-11) that includes injection mechanism 304 attached to the mold.

At block 840, method 800 may inject a material to fill the one or moreporously accessible voided regions with the mold. For example, asdescribed herein, infusion device 301 (e.g., syringe) (FIG. 11) mayinject bulk fluid 302 (FIG. 11) to fill the one or more porouslyaccessible voided regions 215 with the mold 300 (FIGS. 10-11).

At block 850, method 800 may optionally heat the object in an oxygenfree environment until the thermoplastic material undergoes pyrolysis.For instance, as described herein, an oven may heat composite structure211 (FIGS. 9-10) in an oxygen free environment until the thermoplasticmaterial (e.g., bulk 104) undergoes pyrolysis.

At block 860, method 800 may optionally sinter the object into a solidmonolith structure. For example, as described herein, a high temperatureoven may sinter composite structure 211 (FIGS. 9-10) into a solidmonolith structure.

FIG. 21 is a flow diagram illustrating a material injection method inaccordance with some embodiments of the present disclosure.Specifically, method 900 provides for providing a composite structure ona mandrel in accordance with some embodiments. In some embodiments,method 900 may be performed at or by printer 400 (FIGS. 14-15). Someblocks and/or operations in method 900 may be combined, the order ofsome blocks and/or operations may be changed, and some blocks and/oroperations may be omitted.

At block 920, method 900 may rotate a mandrel about an ordinate axis.For example, as described herein, motor 410 (FIG. 14) may rotate amandrel 401 (FIG. 14) about an ordinate axis. In some embodiments, themandrel forms a 3D structure.

At block 930, method 900 may move a filament winding head in a directionparallel to the ordinate axis. For instance, as described herein, motoractuators controlled via controller 160 (FIG. 14) may move a filamentwinding head (FIG. 14) in a direction parallel to the ordinate axis. Insome embodiments, the filament winding head includes a coaxial extruderhead.

At block 940, method 900 may wind a filament core and a viscous liquidaround the mandrel to form the composite material. For example, asdescribed herein, mandrel printer 400 (FIG. 14) may wind a filament core108 (FIG. 14) and a viscous liquid 104 (FIG. 14) around the mandrel 401(FIG. 14) to form the composite material 402 (FIG. 14).

FIG. 22 is a flow diagram illustrating an additive manufacturing processin accordance with some embodiments of the present disclosure.Specifically, method 1000 provides for forming a bulk bead 113A overvoided region 215 in accordance with some embodiments. In someembodiments, method 1000 may be performed at or by coaxial extruder 100and a container of liquid solution 310 (FIGS. 16A-16D). Some blocksand/or operations in method 1000 may be combined, the order of someblocks and/or operations may be changed, and some blocks and/oroperations may be omitted.

At block 1020, method 1000 may form a first support structure made of afirst material and a second support structure made of a second material.For example, as described herein, coaxial extruder 100 (FIG. 16A) mayform a first support structure 130A (FIGS. 16A-16D) made of a firstmaterial 104A (FIGS. 16A-16D) and a second support structure 130B (FIGS.16A-16D) made of a second material 104B (FIGS. 16A-16D). In someembodiments, a region between the first and second support structuresmay be devoid of material and the bulk material is insoluble.

At block 1030, method 1000 may dispose a highly soluble material in theregion between the first and second support structures. For instance, asdescribed herein, coaxial extruder 100 (FIG. 16B) may dispose a highlysoluble material 605 (FIG. 16B) in the region between the first 130A andsecond support structures 130B (FIG. 16A).

At block 1040, method 1000 may extrude an insoluble material over thehighly soluble material. For example, as described herein, coaxialextruder 100 (FIG. 16C) may extrude an insoluble material (e.g. bulk104A) (FIG. 16C) over the highly soluble material 605 (FIG. 16C).

At block 1050, method 1000 may dissolve the highly soluble material. Forinstance, as described herein, liquid solution 310 may dissolve thehighly soluble material 605 (FIG. 16D).

FIG. 23 is a flow diagram illustrating a technique of adding layers overvoid regions accordance with some embodiments of the present disclosure.Specifically, method 1100 provides for removing mandrel 501 afterforming structures on mandrel 501 in accordance with some embodiments.In some embodiments, method 1100 may be performed at or by coaxialextruder 100, first endcap 525 and second endcap 522, and liquidsolution injected via inlet hole 523 and outflow 524 (FIG. 15A). Someblocks and/or operations in method 1100 may be combined, the order ofsome blocks and/or operations may be changed, and some blocks and/oroperations may be omitted.

At block 1120, method 1100 may form a 3D-print structure on a surface ofa cylinder using a highly soluble material to form a mandrel. Forinstance, as described herein, coaxial extruder 100 (FIG. 15A) may forma 3D-print structure 526 (FIG. 15A) on a surface 510 (FIG. 15A) of acylinder (FIG. 15A) using a highly soluble material 605 (FIG. 15B) toform a mandrel 501 (FIG. 15A).

At block 1130, method 1100 may rotate the mandrel about an ordinateaxis. For example, as described herein, motor 401 (FIG. 14) may rotatethe mandrel 501 (FIGS. 14 and 15A-15B) about an ordinate axis.

At block 1140, method 1100 may move filament winding head in a directionparallel to the ordinate axis. For instance, as described herein,controller 160 (FIG. 14) may move filament winding head (e.g., coaxialextruder 100) (FIGS. 14 and 15B) in a direction parallel to the ordinateaxis.

At block 1150, method 1100 may wind a filament around the mandrel andthe first and second endcap to form a layered composite structure. Forexample, as described herein, controller 160 (FIG. 14) may wind afilament (e.g., core 108 and bulk 104 (FIG. 14) around the mandrel 501(FIGS. 14 and 15B) and the first 522 (FIG. 15A-15C) and second endcap522 (FIG. 15A-15C) to form a layered composite structure 502 (FIG.15B-15D).

At block 1160, method 1100 may place a first endcap over a first end ofthe layered composite structure. For example, as described herein, afirst endcap 525 (FIG. 15B-15C) may be placed over a first end of thelayered composite structure 502 (FIG. 15B-15D).

At block 1170, method 1100 may place a second endcap over a second endof the layered composite structure. For instance, as described herein, asecond endcap 522 (FIG. 15B-15C) may be placed over a second end of thelayered composite structure 502 (FIG. 15B-15D). In some embodiments, thesecond endcap includes an inlet hole between an outside surface of thesecond endcap and a region inside the layered composite structure, andan outlet hole between an outside surface of the second endcap and aregion inside the layered composite structure.

At block 1180, method 1100 may inject a solvent into the inlet hole ofthe second endcap. For instance, as described herein, liquid solutionpump (FIG. 15C) may inject a solvent (e.g., liquid solution 310) (FIG.16D) into the inlet hole 523 (FIG. 15C) of the second endcap 522 (FIG.15C). In some embodiments, the solvent dissolves highly soluble materialand exits the outlet of the second endcap.

FIG. 24 is a flow diagram illustrating of multiple layers with someembodiments of the present disclosure. Specifically, method 1200provides for forming a material structure on a surface of an object withimproved material properties (e.g., isometric stiffness and strength) inaccordance with some embodiments. In some embodiments, method 1200 maybe performed at or by controller 160 and coaxial extruder 100 (FIGS.17A-17B). Some blocks and/or operations in method 1200 may be combined,the order of some blocks and/or operations may be changed, and someblocks and/or operations may be omitted.

At block 1220, method 1200 may deposit a first material at a firstlocation on the surface in a first direction. For example, as describedherein, coaxial extruder 100 (FIG. 17A) may deposit a first material(e.g., bulk 104 and core 108) (FIG. 17A) at a first location 145 (FIG.17A) on the surface (e.g., support structure 210) (FIGS. 17A-17B) in afirst direction (e.g., z-direction) (FIG. 17A).

At block 1220, method 1200 may deposit a second material at a secondlocation different from the first location on the surface in the firstdirection. For instance, as described herein, coaxial extruder 100 (FIG.17A) may deposit a second material (e.g., bulk 134 and core 138) (FIG.17A) at a second location 146 (FIG. 17A) different from the firstlocation 145 (FIG. 17A) on the surface (e.g., support structure 210)(FIGS. 17A-17B) in the first direction. In some embodiments, depositingthe second material at the second location forms a cavity region betweenthe first material deposited in the first location and the secondmaterial.

At block 1220, method 1200 may deposit a third material within thecavity region in a third direction different from the first directionand the second direction to form the material structure on the surfaceof the object. For example, as described herein, coaxial extruder 100(FIG. 17A) may deposit a third material (e.g., bulk 144 and core 148)(FIG. 17B) within the cavity region 601 (FIG. 17A) in a third directiondifferent from the first direction and the second direction to form thematerial structure on the surface of the object.

Although the techniques have been described in conjunction withparticular embodiments, it should be appreciated that variousmodifications and alterations may be made by those skilled in the artwithout departing from the spirit and scope of the invention.Embodiments may be combined and embodiments described in connection withan embodiment may stand alone.

What is claimed is:
 1. An extruder head for a printer comprising: a first distribution channel with an entrance and an exit; a second distribution channel with an entrance and an exit; a priming chamber disposed at the exit of the second distribution channel; a heating element disposed along the second distribution channel and near the priming chamber; and a nozzle disposed at an exit of the priming chamber.
 2. The extruder head of claim 1, further comprising: a first insertion actuator configured to insert a first material into the entrance of the first distribution channel; and a second insertion actuator configured to insert a second material into the entrance of the second distribution channel.
 3. The extruder head of claim 1, wherein the priming chamber surrounds the first distribution channel.
 4. The extruder head of claim 1, further comprising a blade disposed proximate to the exit of the first distribution channel and proximate to the nozzle of the priming chamber.
 5. The extruder head of claim 1, further comprising a thermal barrier interposed between the exit and an entrance of the second distribution channel.
 6. The extruder head of claim 1, further comprising: a cutting chamber disposed above or within the priming chamber and bisecting the first distribution channel; and a blade within the cutting chamber.
 7. The extruder head of claim 1, wherein the exit of the first distribution channel and the nozzle of the priming chamber are adjacent.
 8. An active molding system comprising: a printer having an extruder head; and a shaping actuator configured to follow a displacement of the extruder head, wherein the shaping actuator includes: a pressure regulator configured to maintain a defined pressure applied to an exposed layer of material, and a foot unit that shapes the exposed layer of material; and a controller configured to control the printer and the shaping actuator.
 9. The active molding system of claim 8, wherein the foot unit of the shaping actuator is a roller.
 10. The active molding system of claim 8, wherein the shaping actuator includes a continuous tread.
 11. The active molding system of claim 8, wherein the shaping actuator includes an air nozzle configured to force air to impinge on the exposed layer of material.
 12. The active molding system of claim 8, wherein the foot unit of the shaping actuator is one of cambered or flat.
 13. The active molding system of claim 8, wherein the shaping actuator includes a blade.
 14. The active molding system of claim 13, further comprising a pulsator that pulses the blade between a first position and a second position.
 15. The active molding system of claim 8, wherein the shaping actuator includes a temperature regulator configured to maintain a defined temperature at the exposed layer of material, and the controller is configured to control the temperature regulator.
 16. The active molding system of claim 15, wherein the temperature regulator includes one or both of a temperature sensor or a heating element.
 17. The active molding system of claim 16, wherein the heating element is an electrical heating element.
 18. The active molding system of claim 16, further comprising a laser configured to heat the exposed layer, and the controller is configured to control the laser.
 19. The active molding system of claim 18, wherein the laser outputs in one of an ultraviolet spectrum or infrared spectrum.
 20. The active molding system of claim 8, wherein the foot unit includes an actuator that generates sonic or ultrasonic pulses. 